Enhanced photic driving (PD) during high-frequency flicker stimulation, the so-called H response, is a classical feature of migraine patients between attacks, but is thought to be of poor clinical utility ... [more ▼]

Enhanced photic driving (PD) during high-frequency flicker stimulation, the so-called H response, is a classical feature of migraine patients between attacks, but is thought to be of poor clinical utility. Visual inspection of the EEG for its detection may not be reliable, however, data on its possible correlations with clinical features and migraine pathophysiology are scarce. We have compared visual inspection and EEG spectral analysis to detect abnormal PD in 280 consecutive migraine patients of our headache clinic (episodic migraine without aura, n = 171; chronic migraine, n = 48; migraine with aura, n = 61) and in a group of 24 non-migrainous neurological controls. Spectral frequency analyses were performed blindly by one of us (YF). On visual inspection, 50.4 % of migraineurs were thought to have increased 20 Hz PD. After spectral analysis, only 62.4 % of them had PD power superior to the mean + 95 % CI of the control group. Sensitivity of visually identified PD was 82.24 %, specificity 69.36 %. Increased PD on spectral analysis was more prevalent in episodic migraine than in chronic migraine, in patients with low attack frequency, in those with ictal autonomic symptoms in addition to nausea and in those with a strong family history of migraine. We confirm therefore that 20 Hz photic driving is of little diagnostic utility and its prevalence in migraine overestimated on visual inspection. Its presence on spectral analysis of the EEG, however, might be of pathophysiological interest, as it identifies subgroups of migraineurs of whom the common denominator could be lack of habituation of cortical responses during repetitive stimulation. [less ▲]

Introduction Perception of duration has a major impact on the child’s ability to manage everyday life. Usually, the perception of time is considered in its sequential component. To our knowledge, possible ... [more ▼]

Introduction Perception of duration has a major impact on the child’s ability to manage everyday life. Usually, the perception of time is considered in its sequential component. To our knowledge, possible semiological markers for the capacity to apprehend temporal duration have not yet been explored. There are thus no existing tools either for its evaluation (in everyday life) or for the description of its development during childhood. We are thus largely in the dark about how the perception of duration develops during childhood. Hypothesis 1) It is possible to track perception of duration using semiological markers in everyday life; 2) Children with developmental disorders can be expected to develop difficulties in this domain. Method We designed a questionnaire for parents using a Likert scale. The questionnaire was administered to 2 samples from 2:6 to 13 years: 827 in a general population and 297 in a mixed-psychopathological population recruited from the Mental Health Services network. We carried out a multinomial logistic regression and used percentiles curves (P5,50,95). Results In the general population, perception of duration is gradually acquired and full competence is attained by 9 years. The apprehension of sequential time is achieved by 4 years. In the psychopathological sample, mean perception of temporal duration is delayed by 18 months and significant difficulties remain even at 13 years. The apprehension of sequential time is also delayed: even at 13 years it remains low (at percentile 95). We have found no sex-related differences. Discussion Perception of duration is an important developmental feature which has not been taken into account until now. Semiological markers can be used to differentiate typically developing children from clinical populations as to their respective capacities to perceive temporal duration. [less ▲]

Post-dispersal fate of seeds dispersed by large primates is well studied but little is known about this process in small frugivores like tamarins. This study in the Amazonian forest of Peru aimed at ... [more ▼]

Post-dispersal fate of seeds dispersed by large primates is well studied but little is known about this process in small frugivores like tamarins. This study in the Amazonian forest of Peru aimed at investigating if characteristics related to the defecation patterns of tamarins (Saguinus mystax and Saguinus fuscicollis) affected short-term post-dispersal seed fate, through secondary seed dispersal by dung beetles and removal by seed predators. Data on dung beetle activity were based on direct observations of 49 defecations while seed fate was studied using semi-controlled experiments (N = 458 for secondary dispersal and N = 398 for predation). Tamarins produce small defecations with a low number of seeds. Thirty-five per cent of defecations were visited by an average of 1.5 dung beetles that usually transport the faeces as pellets. Twenty-four per cent of seeds were buried by beetles at a mean depth of 3.5 cm. With increasing quantities of faecal matter, the probability of secondary seed dispersal increased but not the depth of burial. Seed predation pressure was low (17.6%) after 4 d and higher in faeces of S. mystax than in faeces of S. fuscicollis. Despite their small size, tamarins could be considered as high-quality seed dispersers, with a potential role for forest regeneration. [less ▲]

INTRODUCTION: Functional residual capacity (FRC) measurement is now available on new ventilators as an automated procedure. We compared FRC, static thoracopulmonary compliance (Crs) and PaO2 evolution in ... [more ▼]

INTRODUCTION: Functional residual capacity (FRC) measurement is now available on new ventilators as an automated procedure. We compared FRC, static thoracopulmonary compliance (Crs) and PaO2 evolution in an experimental model of acute respiratory distress syndrome (ARDS) during a reversed, sequential ramp procedure of positive end-expiratory pressure (PEEP) changes to investigate the potential interest of combined FRC and Crs measurement in such a pathologic state. METHODS: ARDS was induced by oleic acid injection in six anesthetised pigs. FRC and Crs were measured, and arterial blood samples were taken after induction of ARDS during a sequential ramp change of PEEP from 20 cm H2O to 0 cm H2O by steps of 5 cm H2O. RESULTS: ARDS was responsible for significant decreases in FRC, Crs and PaO2 values. During ARDS, 20 cm H2O of PEEP was associated with FRC values that increased from 6.2 +/- 1.3 to 19.7 +/- 2.9 ml/kg and a significant improvement in PaO2. The maximal value of Crs was reached at a PEEP of 15 cm H2O, and the maximal value of FRC at a PEEP of 20 cm H2O. From a PEEP value of 15 to 0 cm H2O, FRC and Crs decreased progressively. CONCLUSION: Our results indicate that combined FRC and Crs measurements may help to identify the optimal level of PEEP. Indeed, by taking into account the value of both parameters during a sequential ramp change of PEEP from 20 cm H2O to 0 cm H2O by steps of 5 cm H2O, the end of overdistension may be identified by an increase in Crs and the start of derecruitment by an abrupt decrease in FRC. [less ▲]

In acute pulmonary embolism, right ventricular (RV) failure may result from exceeding myocardial contractile resources with respect to the state of vascular afterload. We investigated the adaptation of RV ... [more ▼]

In acute pulmonary embolism, right ventricular (RV) failure may result from exceeding myocardial contractile resources with respect to the state of vascular afterload. We investigated the adaptation of RV performance in a porcine model of progressive pulmonary embolism. Twelve anesthetized pigs were randomly divided into two groups: gradual pulmonary arterial pressure increases by three injections of autologous blood clot (n = 6) or sham-operated controls (n = 6). Right ventricular pressure-volume (PV) loops were recorded using a conductance catheter. Right ventricular contractility was estimated by the slope of the end-systolic PV relationship (Ees). Afterload was referred to as pulmonary arterial elastance (Ea) and assessed using a four-element Windkessel model. Right ventricular-arterial coupling (Ees/Ea) and efficiency of energy transfer (from PV area to external mechanical work [stroke work]) were assessed at baseline and every 30 min for 4 h. Eaincreased progressively after embolization, from 0.26 +/- 0.04 to 2.2 +/- 0.7 mmHg mL (P < 0.05). Ees increased from 1.01 +/-0.07 to 2.35 +/- 0.27 mmHg mL (P < 0.05) after the first two injections but failed to increase any further. As a result, Ees/Ea initially decreased to values associated with optimal SW, but the last injection was responsible for Ees/Ea values less than 1, decreased stroke volume, and RV dilation. Stroke work/PV area consistently decreased with each injection from 79% +/- 3% to 39% +/- 11% (P < 0.05). In response to gradual increases in afterload, RV contractility reserve was recruited to a point of optimal coupling but submaximal efficiency. Further afterload increases led to RV-vascular uncoupling and failure. [less ▲]

in Journal of Pharmacokinetics and Pharmacodynamics (2007), 34(4), 549-558

Once-daily dosing almost invariably shows a slightly higher percentage of prescribed doses taken than does twice-daily dosing. Many pharmaceutical scientists, regulators, and prescribers have considered ... [more ▼]

Once-daily dosing almost invariably shows a slightly higher percentage of prescribed doses taken than does twice-daily dosing. Many pharmaceutical scientists, regulators, and prescribers have considered this finding to signify the therapeutic superiority of once-daily dosing. The therapeutically more relevant question, however, is not the percentage of prescribed doses taken but the comparative impact of missed doses on the pharmacologic effects of a drug under the two dosing regimens. A key point in this regard is that the pharmacokinetic equivalent of a single missed once-daily dose is 2-3 sequentially omitted twice-daily doses. Thus, an important parameter in comparing the two regimens is the probability of two or three twice-daily doses being sequentially omitted, versus the probability of missing a single once-daily dose. Our data indicate that the probability of sequential omission of 2-3 twice daily doses is half the probability of omission of a single once-daily dose. For that reason, a twice-daily regimen could prove to be superior to a once-daily regimen in maintaining drug concentrations within a therapeutically desirable range. A more important consideration, however, is to maintain not just the concentration of drug in plasma, but the drug's therapeutic action. The duration of therapeutic drug action following a last-taken dose is not only drug-specific, but also, for some drug, dependent on the pharmacodynamic properties. Judging the comparative superiority of one dosing regimen over another requires knowledge of the drug's duration action after a last-taken dose, plus knowledge of the comparative probabilities of the various patterns of dose omission. When applied to HIV protease inhibitors, a twice-daily regimen appears to be better than an once-daily regimen in maintaining therapeutically effective drug actions. [less ▲]

A case of dilated ischemic cardiomyopathy, with severely impaired left ventricular systolic function, treated by endoventriculoplasty and CABG, is reported. The authors discuss the modern concepts ... [more ▼]

A case of dilated ischemic cardiomyopathy, with severely impaired left ventricular systolic function, treated by endoventriculoplasty and CABG, is reported. The authors discuss the modern concepts regarding the surgical treatment of large anterior asynergic scars following occlusion of the LAD. Since there are more similarities between akinesia and dyskinesia than previously thought, the endoventriculoplasty of DOR may constitute a new way to surgically remodel the left ventricle in dilated cardiomyopathies with large anterior akinesia. This surgery significantly improves the ventricular function and the overall patients' prognosis at short and mid term follow up. [less ▲]

BACKGROUND: Physical inactivity is a major atherosclerosis risk factor. The exercise tolerance is usually excellent after neonatal arterial switch operation, but those patients in whom coronary anomalies ... [more ▼]

BACKGROUND: Physical inactivity is a major atherosclerosis risk factor. The exercise tolerance is usually excellent after neonatal arterial switch operation, but those patients in whom coronary anomalies remain the main late complication, risk developing atherosclerotic coronary disease owing to perceived physical activity restrictions. METHODS: We investigated physical activity patterns of 52 unselected children 7 to 14 years after neonatal arterial switch operation for transposition of the great arteries by 24-hour continuous heart rate monitoring. The percentage of heart rate reserve was used to measure the amounts of activities. Comparisons were made with 35 children with repaired atrial or ventricular septal defect and with 127 age-matched healthy children. RESULTS: Children after arterial switch operation accumulated 167.3 +/- 70.6, 25.3 +/- 12.9, and 15.7 +/- 11.3 minutes a day (mean +/- SD) of light, moderate, and vigorous physical activities, respectively. At the same activity levels, children with repaired septal defect accumulated 165.2 +/- 82.2, 26.2 +/- 11.7, and 16.2 +/- 9.1 minutes a day, and their healthy peers 164.8 +/- 74.5, 31.8 +/- 13.9, and 21.9 +/- 11.3 minutes a day. Both cardiac groups were significantly less active than the control group when considering moderate (p = 0.026) and vigorous activities (p = 0.006). Only 19% and 27% of the children after arterial switch operation engaged, respectively, in more than 30 minutes a day of moderate activity and 20 minutes a day of vigorous activity. CONCLUSIONS: Children after arterial switch operation, just like other cardiac children, do not meet the guidelines for physical activity. We should encourage regular physical activity to offset adult sedentary behavior and to prevent atherosclerotic cardiovascular disease in those patients whose long-term function of the coronary arteries remains a matter of concern. [less ▲]

The influence of subject misclassification on log-linear analysis of two-way contingency tables is investigated. We define pairwise misclassification and focus on both deviance and Pearson statistics as ... [more ▼]

The influence of subject misclassification on log-linear analysis of two-way contingency tables is investigated. We define pairwise misclassification and focus on both deviance and Pearson statistics as goodness-of-fit criteria for testing independence between the variables. Attention is paid to the extremal values of the test statistics that can be reached on the basis of the data set. We derive theoretical properties and use them to detect potentially troubling cells in a simple computing routine. Examples illustrate our purpose. [less ▲]

Background: Patients with acute pulmonary embolism (APE) present with a broad spectrum of prognoses. Computed tomographic pulmonary angiography (CTPA) has progressively been established as a first line ... [more ▼]

Background: Patients with acute pulmonary embolism (APE) present with a broad spectrum of prognoses. Computed tomographic pulmonary angiography (CTPA) has progressively been established as a first line test in the APE diagnostic algorithm, but estimation of short term prognosis by this method remains to be explored. Methods: Eighty two patients admitted with APE were divided into three groups according to their clinical presentation: pulmonary infarction (n=21), prominent dyspnoea (n=29), and circulatory failure (n=32). CTPA studies included assessment of both pulmonary obstruction index and right heart overload. Haemodynamic evaluation was based on systolic aortic blood pressure, heart rate, and systolic pulmonary arterial pressure obtained non-invasively by echocardiography at the time of diagnosis of pulmonary embolism. Results: The mortality rate was 0%, 13.8% and 25% in the three groups, respectively. Neither the pulmonary obstruction index nor the pulmonary artery pressure could predict patient outcome. In contrast, a significant correlation with mortality was found using the systolic blood pressure (p<0.001) and heart rate (p<0.05), as well as from imaging parameters including right to left ventricle minor axis ratio (p<0.005), proximal superior vena cava diameter (p<0.001), azygos vein diameter (p<0.001), and presence of contrast regurgitation into the inferior vena cava (p=0.001). Analysis from logistic regression aimed at testing for mortality prediction revealed true reclassification of 89% using radiological variables. Conclusion: These results suggest that CTPA quantification of right ventricular strain is an accurate predictor of in-hospital death related to pulmonary embolism. [less ▲]

This study investigated the effects of dobutamine on left ventriculoarterial (VA) coupling and mechanical efficiency in acutely ischemic pigs. Experiments were performed in 12 pigs in which vascular ... [more ▼]

This study investigated the effects of dobutamine on left ventriculoarterial (VA) coupling and mechanical efficiency in acutely ischemic pigs. Experiments were performed in 12 pigs in which vascular properties, including peripheral resistance (R-2), compliance (C), and arterial elastance (E-a), were estimated with a windkessel model, and left ventricular (LV) function by the slope (E-es) of the end-systolic pressure-volume relationship (ESPVR) and stroke work (SW). VA coupling was defined as E-es/E-a, and mechanical efficiency as SW/pressure-volume area (PVA). In all animals, the left anterior descending coronary artery was ligated after basal measures. The animals were then randomly divided into 2 groups: group CTRL (n = 6) was followed for 180 minutes without other intervention, whereas group DOBU (n = 6) was infused with dobutamine (5 mug(.)kg(-1.)min(-1)) starting after T60 measures. Coronary occlusion induced a rightward shift of ESPVR and a decrease in E-es from 3.67 +/- 0.33 to 1.92 +/- 0.20 mm Hg(.)mL(-1), while E-a changed from 3.33 +/- 0.56 to 4.65 +/- 0.29 mm Hg(.)mL(-1), R-2 from 1.72 +/- 0.30 to 2.38 +/- 0.16 mm Hg(.)s(.)mL(-1), and C from 0.78 +/- 0.16 to 0.46 +/- 0.08 mL(.)mm Hg-1. This altered VA coupling from 1.22 +/- 0.11 to 0.44 +/- 0.07. SW decreased from 4056 +/- 223 to 2372 +/- 122 mm Hg(.)mL, and PVA and SW/PVA decreased from 5575 +/- 514 to 4830 +/- 3.17 mm Hg(.)mL, and from 0.76 +/- 0.04 to 0.49 +/- 0.03, respectively. In group DOBU, dobutamine restored E-es and the position of ESPVR to baseline values, while E-a decreased to 3.39 +/- 0.34 mm Hg(.)mL(-1) because of an R-2 decrease to 1.60 +/- 0.24 mm Hg(.)s(.)mL(-1). VA coupling was restored. SW and PVA increased to 3833 +/- 180 mm Hg(.)mL and to 7498 +/- 442 mm Hg(.)mL, respectively, while SW/PVA was unchanged. In ischemic pigs, dobutamine restored VA coupling through an increase in LV contractility and decrease in arterial elastance as a result of peripheral vasodilatation. However, myocardial oxygen consumption was increased, and mechanical efficiency impaired. [less ▲]

AIMS: In patients with heart failure and chronic ischaemic mitral regurgitation (MR), the mortality risk is related to the quantified severity of MR at rest and its dynamic changes during exercise. The ... [more ▼]

AIMS: In patients with heart failure and chronic ischaemic mitral regurgitation (MR), the mortality risk is related to the quantified severity of MR at rest and its dynamic changes during exercise. The impact of dynamic MR on long-term mortality, hospital admission for heart failure, and major adverse cardiac events has never been investigated. METHODS AND RESULTS: We prospectively studied 161 patients with chronic ischaemic left ventricular (LV) dysfunction and at least mild MR who underwent quantitative measurement of the effective regurgitant orifice (ERO) of MR at rest and during semi-supine exercise test and who were followed up for 35+/-11 months. The 20 patients who underwent surgery were censored at the time of operation. Of the 141 patients who were treated medically, 23 died, 22 required hospitalization for heart failure, 4 had nonfatal myocardial infarction, and 11 developed unstable angina. By multivariate analysis, an exercise-induced increase in ERO by > or =13 mm(2) and a greater increase in transtricuspid pressure gradient during exercise emerged as predictors of mortality and of hospital admission for heart failure. MR severity under basal conditions (ERO> or =20 mm(2)) was an independent predictor of only cardiac death. Greater LV volumes at rest and lack of contractile reserve during exercise were additional independent markers of poor outcome. CONCLUSION: In patients with ischaemic heart disease and LV dysfunction, large exercise-induced increases in MR identify patients at high risk of morbidity and of death. [less ▲]

Rapid restoration of coronary blood flow following a period of myocardial ischemia (due to coronary occlusion) is mandatory to preserve the cardiac muscle. Reperfusion, however, not necessarily restores ... [more ▼]

Rapid restoration of coronary blood flow following a period of myocardial ischemia (due to coronary occlusion) is mandatory to preserve the cardiac muscle. Reperfusion, however, not necessarily restores cardiac function, and cellular damage of the cardiac muscle cells following reperfusion (reperfusion injury) is well documented. The aim of this study was to investigate the effects of reperfusion on left ventricular (LV) hemodynamics and on left ventriculo-arterial (VA) coupling in acutely ischemic pigs. [less ▲]

The purpose of this study was to compare the hemodynamic effects of pentobarbital and propofol and their effects on cardiovascular adaptation to an abrupt increase in left ventricular afterload ... [more ▼]

The purpose of this study was to compare the hemodynamic effects of pentobarbital and propofol and their effects on cardiovascular adaptation to an abrupt increase in left ventricular afterload. Experiments were performed in 12 open-chest pigs instrumented for measurement of aortic pressure and flow, and left ventricular pressure and volume. In one group (n = 6), anesthesia was obtained with sodium pentobarbital (3 mg x kg(-1) x h(-1)), and, in the second group B (n = 6), with propofol (10 mg x kg(-1) x h(-1)). Both groups received sufentanil (0.5 microg x kg(-1) x h(-1)) and pancuronium bromide (0.1 mg x kg(-1)). Left ventricular function was assessed by the slope of end-systolic pressure-volume relationship and stroke work. After baseline recordings, left ventricular afterload was increased by aortic banding. The cardiovascular adaptations triggered by the aortic banding, such as tachycardia, vasoconstriction, and augmentation of myocardial contractility were prevented with propofol, suggesting interference with the baroreflex. Increase in left ventricular afterload decreased mechanical efficiency, regardless of anesthetic agent. These results showed that pentobarbital at 3 mg x kg(-1) x h(-1) has less deleterious hemodynamic effects than propofol at 10 mg x kg(-1) x h(-1). [less ▲]

OBJECTIVE: To compare the sensitivity of cystatin C and creatinine in detecting decreased glomerular filtration rate. DESIGN: Prospective observational study. SETTING: Medical intensive care unit at a university hospital. PATIENTS AND PARTICIPANTS: Fourteen patients hospitalised in a medical intensive care unit. INTERVENTIONS: Cystatin C and creatinine plasmatic levels were measured in 40 blood samples taken with an interval of at least 24 h. MEASUREMENTS AND RESULTS: Glomerular filtration rate was estimated by creatinine clearance using 24-h urine collection and the classical Cockcroft-Gault equation. The ability of cystatin C to detect a glomerular filtration rate under 80 ml/min per 1.73 m(2) was significantly better than that of creatinine ( p<0.05). CONCLUSIONS: Cystatin C, a new plasmatic marker of renal function, could be used to detect renal failure in intensive care in the future. [less ▲]